Tool-operating machine



ril 6 1926. Ap A. WHITE TOOL OPERATING MACHINE Filed June 20, 1925 6 Sheets$heet 1 IN l/ENTOR ATTQRNEY A. WHITE TOOL OPERATING MACHINE April 6 1926. 1,580,094

Filed June 29, 192:5 e sheets-5mm 2 F1 W 171' 10 50 i i 1 W W Z i A ril 6', 1926.

A. WHITE TOOL OPERATING MACHINE Filed June 20, 1923 6 Sheets-Sheet 5 //\/1/EN TOR.

ATTORNE April 6 1926. 1,580,094

A. WHITE TOOL OPERATING MACHINE Filed June 20, 1923 6 Sheets-Sheet 5 A TT ORNE Y.

A. WHITE TOOL OPERATING MACHINE April 6 Filed June 20, 19275 6 Shets-Sheet 6 l/ENTQR-' ATTo kA/EY Patented Apr. 6 1926. 1

UNITED STATES PATENT OFFICE.

ALPHONZO WHIT'E, OF WINCHENDON, MASSACHUSETTS,'ASSIG1\TOR TO BAXTER D. WHITNEY & SON, INC., 01: WINCHENDON, MASSACHUSETTS, A" CORPORATION OF MASSACHUSETTS.

TOOL-OPERATING MACHINE.

Application filed June a0, 1923. Serial No. 646,561.

tools, and is well adapted to move various types oftools into and out of engagement with the work." i I The hydraulic operating means of the present invention is well adapted to move the bit and hollow chisel of a wood working machine or a drill of a boring machine into and out of engagement with the work. to operate a punch, stamping die,.-lproaching tool or various other tools which are.. mo"ed into and out of engagement with the work, or over the face of the work with a cutting action;

In operating the above mentioned tools it may be desirable to-move the tools back and forth with a reciprocatory movement between different selected points lying within the limits of the path of travel of the hy dranlic operating means, and it is important that the operating means he completely under the control of the operative so that the movement of the tool toward the work may be stopped. immediately in any position of its advancement.

One important feature of the present invention, therefore, resides in hydraulic operating means for imparting movement to a tool to cause it to reciprocate between selected points that may be readily adjusted, and in means under the control ofthe operative for quickly arresting the. tool in any position of advancement toward the work and returning the tool to its starting position.

Another feature of the present invention resides in means that may be readily controlled by the operative for imparting the initial stroke to the tool to cause it to reciprocate repeatedly between selected points, and for imparting a final stroke to the tool that relieves it from the operation of the reciprocating means. In the embodiment of the invention shown this desired control is obtained by operating a foot treadle which may be depressed by the operative to impartthe reciprocative movement to the tool so that the tool will move back and forth repeate'dly as long as the treadle is depressed but will be arrested promptly in its movement toward the work and returned to its starting position by releasing the foot treadle.

Another feature of the invention resides in means for operating the tool with a slow working stroke and a quick return, and in means for withdrawing the tool a maximum distance from the work as soon as its reciprocating movement is arrested and for holding the "tool in this position.

Another feature ofthe invention resides in the liquid control means for obtaining the desired hydraulic operation of the tool.

The above and other features of the invention and novel combination of parts will be hereinafter described in connection with the accompanying drawings which show one good practical form of the invention.

In the drawings:

Fig. 1 is a side elevation of a machine constructed in accordance with the present 1nvent1on.

Fig. 2 is an enlarged rear elevation of the Fig. 5 is an enlarged perspective view with parts in section of a reverse lever .to be described. I

Fig. 6 is a sectional view taken on the line 66 of Fig. 3.

Fig. 7 is a sectional View taken on the line 77 of Fig. 1.

Fig. 8 is a. face view of the hydraulic cylinder looking in the direction of the arrows 8-8 of Fig. 3. i

Fig. 9 is a face view of-the valve chest for the hydraulic cylinder looking in the di rection of the'arrows 9-9 of Fig. 31-

Fig. 10 is a sectional view taken on the line 1010 of Fig. 1. l

Fig. 11 is a perspective view of the hycooperating faces in spaced relation.

portion of the machine shown in I Fig. 12 is a vertical sectional view similar to Fig. 3, but taken in the plane of the port leading to the lower end of the cylinder; and

Fig. 13 is a face view of the spool at the lower end of the piston shaft.

Referring to the drawings: The machine shown therein as one good form of the invention has a suitable base upon which the frame 11 in the form of a column is mounted, and the frame or column 11 is provided at its upper end with a laterally extending portion 12 upon which the head 13 is slidably mounted. This head'is adapted to carry the tool such as a bit and hollow chisel 14 to be operated, and the head 13 is adapted to be moved back and forth in a vertical direction by hydraulic means to be described. Below the head 13 may be provided a work supporting table 15 of any preferred construction, and this table may be secured to the frame or column 11 for vertical adjustment to different heights from the base 10, and the screw 16 operated by the hand wheel 17 is provided to raise the table 15.

As stated the hydraulic operating means of the present invention is well adapted to impart a reciprocatory movement to various types of tools and the construction of the parts so far described obviously may be varied as desired to meet the requirements of the class of work to be done [by the hydraulically operated tool.

In the present case at the upper end of the frame 11 is provided a cylinder 18 in which is slidably mounted the piston 19, and this piston has a downwardly extending piston shaft 20 which extends through a casing 21 formed below the piston chamber 22, and this shaft passes through a stufling-box 23 of any appropriate construction. The head 13 may be variously constructed, depending upon the type of tool to be carried and operated thereby, and in the present case is shown as having a substan tial cylindrical body adapted to receive a driving motor and is provided with laterally extending flanges 24 which slidably engage the vertical face 25 of the frame 11 and fit slidably within the dovetail guideway best shown in Fig. 4. The sliding head 13 may be provided at its lower end with a chuck or other tool holding means 26.

Sliding movement is imparted to the head 13 by the piston 19, and to this end the piston shaft 20 has a reduced portion 27 at its lower end upon which the spool 28 is secured (see Figs. 4 and 13), the spool being clamped between the shoulder 27 at the upper end of the reduced portion 27 and a nut 29 at the lower end of the shaft. The sliding head 13 is provided with an outwardly' extending bracket 30 having .the arcuate portion 31 best shown in Fig. 4 which fits between the opposite heads 32 of the spool and embraces the body portion of the spool. The arrangement is such that the bracket 30 may slide laterally slightly between the flanges of the spool to thereby allow for a slight relative movement between the piston shaft 20 and head 13 in case the two do not travel in absolutely parallel relation.

It is desirable to provide means for counter balancing the weight of the sliding head 13 and associate parts, and to this end in the present case a pulley 33 (see Fig. 3) is mounted within the hollow frame or column 11 upon the transversely extending shaft 34, and a strap or chain 35 having one end secured to the spool 28 passes around the pulley 33, and has its opposite end secured to this pulley so that as the head 13 slides downwardly the strap 35 will unwind from the pulley 33, and as the head moves upwardly this strap will wind about the pulley. A cam head 36 is mounted upon the shaft 34 and is rigidly secured to the pulley 33 and a chain 37 has one end secured to this cam as best shown in Fig. 3, and the opposite end of this chain is secured to a spring 38, the arrangement being such that the spring exerts a downward pull upon the cam 36, which tends to rotate the same 1n a contra-clockwise direction to wind the strap 35 about its pulley, and when the head 13 moves downwardly it will rotate the pulley 33 in a clockwise direction, and this will wind the chain 37 about its cam head and tension the spring 38. The cam-shape given to the cam head 36 serves to compensate for variations in the strength of the spring 38 under different conditions of tension.

Various fluids may be supplied to the cylinder 18 to operate the piston, but a nonexpansible fluid such as oil or water is preferable because a non-expansible fluid or liquid will force the piston downwardly at a uniform rate of speed and will not be affected by variations in the resistance offered to the downward movement by the tool 14, whereas an expansible fluid will be compressed with the increase in resistance to the downward movement of the tool and this 'will permit variation in the speed-at which the tool is forced into its work. In the construction shown the operating liquid is supplied to the cylinder 18 by a rotary pump 39 which may be mounted upon a tank 40 secured to the base 10 of the machine, and the liquid may pass from the pump 39 to the valve casing 41 through a pipe 42, and this liquid alter passing through the various valves and the piston chamber is returned to the tank 40 through the pipe 43 the lower end of which extends into a con duit 44 leading into a side of the tank 40.

In the embodiment of the invention illustrated the pressure of the operating fluid upon the opposite faces of' the piston 19 is controlled by a main 'valve 45, and the main valve in turn is controlled by an auxiliary valve 46, which auxiliary valve is shifted back and forth by a reverse lever 47 to be described. Since the present invention is designed more particularly to use a non-expandi-ngliquid as the operating medium, it is desirableto shift the-main valve by fluid pressure rather than by some positive mechanical movement, due to the fact that it is necessary to permit the main valve to hesitate-slightly while being shifted so that the non-yielding liquid may escape from the valve without being trapped, and a liquid which exerts a predetermined pressure upon the main valve to shift the same meets this condition very satisfactorily.

The construction of the main and auxiliary valves may be varied as desired, and one good practical construction of these valves and their valve chambers will now be described. The valve casing 41 is shown as having the flat face 48 adapted to be firmly secured to the flat face 49 of the cylinder 18 (see Figs. 8, 9 and 11), and the valve casing 41 is provided with the ports 50 and 51 that lead from the main valve, and these ports communicate with theports 52 and 53 respectively, the arrangement. is such that the'liquid passes through the ports 50 and 52 to the upper end of the cylinder 18 and passes through the ports 51 and 53 to the lower end ofthe cylinder. The main valve 45 is mounted within the mam valve chamber 54 and this chamber is cylindrical in form and extends transversely of the valve casing 41. The ends of the chamber 54 are closed by cap plates 55 having hollow inwardly extending bosses 56. About the the main valve is moved to the position central portion of the chamber 54 is formed an annular pocket 57 communicating with the high pressure chamber 58, and to either side of the pocket 57 are formed annular pockets 59 and 60 arranged to be placed by the main valve 45 in communication with the high pressure pocket 57 or the low pres sure pockets 61 and 62 surrounding the main valve. The ends of the valve 45 are slidably received in the hollow bosses 56, and about the valve is formed annular flanges 63 and 64. The arrangement is such that if shown in Fig. 6, the oil or other liquid from the high pressure chamber 58 'will pass from the pocket 57 into the valve chamber between the flanges 63 and 64 and then out through the pocket 60 to the port 50 (see' Fig. 9) leading to the upper end of the cylinder18; and while'the valve 45 remains in this position, communication is established between the lower end of the cylinder 18 and the low pressure pocket 61 by the ports 58 and 51 leading from the bottom of the cylinder chamber to the pocket 59 (see Fig.

12). If the valve 45 is'nioved to the opposite end of its chamber, communication willbe established between the high pressure pocket 57 and pocket 59, and between the low pressure pocket 62 and pocket 60. The low pressure pockets 61 and 62 open into the low pressure chamber 65.

As stated it is found desirable to operate the main valve through an auxiliary valve rather than by mechanical connections be tween the main valve and reverse lever 47. In the present instance the main valve is shifted by establishing liquid pressure at first one end of the valve, and then the other. This is accomplished by providing an auxiliary valve chamber 66 (see Fig. 7) extending transversely of the valve casing 41 in.

which the auxiliary valve 46 is s'lidably mounted, and this auxiliary valve chamber communicates with the low pressure chamberthrough a port 67, and upon each side of the pointwhere the port 67' enters this chamber are provided ports 68 and 69 lead ing from the chamber 66 to conduits 70 and 71 (see Figs. 9 and 10). The conduit 70 communicates with the chamber 54 at one end of the main valve through inclined port the same time liquid is permitted to escape from the right-hand end of the main valve through port 73, conduit 71, port 69, into the chamber 66 of the auxiliary valve, and from this chamber through port 74, to the curved conduit 75* (Fig. 9) which discharges thru port 76 into the liquid space at a point below therelief pressure valve 77 located.

between the low pressure chamber 65. and the pipe 43 through which liquid returns to the tank 46 at the base of the machine. If theauxiliary valve 46 is shifted from the position shown in. Fig. 6 to the position shown in Fig. 7, the liquid will pass from port 67 to 69 and then to one end of the valve 45 and will escape from the other end of this valve through port 72,- conduit 70,

port 68, .valve chamber 66, port 79, curved conduit 80, into the port 76. The curved conduits' 75 and 80, it should be noted extend entirely around the face of the valve chest shown in Fig. 9 and serve to collect any liquid that may escape from the ports they' surround.

It is desirable in most cases to provide means for moving the tool toward and from the work with a'slow working stroke and a quick return to reduce the time consumed in removing the tool from its work, and in the present case this is accomplished by providon movement of the piston to the upper end 9 ing the piston 19 with a large shaft portion 81 within the chamber 22 and which portion is constructed to slide within the reduced collar 82 formed between the cylinder 18 and casing 91. As a result of this construction the upper face of the piston 19 has a larger area which is exposed to the liquid than the lower "face .qfthis piston, and a larger amount of liquid is required to fill the chamber above the piston 19 as the latter is forced downwardly than is required to fill the chamber below this piston as the piston is forced upwardly. The lower casing 21 preferably has a chamber 83 formed therein which is of sufficient size to receive the enlarged portion 81. freely as the piston is forced downwardly and this chamber 83 communicates with the low pressure chamber 65 through a conduit 84. The arrangement is such that as the piston 19 moves downwardly the liquid crowded out of the chamber 83 by the enlarged portion 81 is free to flow into the low pressure chamber 65 and may escape from the chamber 65 through the relief valve 77 which is yieldingly held in place by the spring 85.

Since the hydraulic means of the present invention is preferably operated by a noncompressible fluid it is desirable to maintain a continuous flow of the operating liquid to the high pressure chamber 58 and not to interrupt this flow when the piston comes to rest at the upper end of its stroke. In the present construction the enlarged portion 81 of the piston shaft is therefore provided with passages 86 which are opened upof its stroke, and these passages permit the liquid within the chamber 22 to escape therefrom through the passages 86 and into-the chamber 83 and low pressure chamber 65. As a result of this construction as long as the piston 19 is in its uppermost position the liquid may flow from the main valve 45 through the port 53 to the lower end of the cylinder 18 and may then escape through the passages 86 into the low pressure chamber.

This serves to maintain a pressure. upon the under face of the piston 19 corresponding to the pressure in the low pressure chamber 65 to maintain the piston in its uppermost position, and this in turn serves to hold the sliding head 13 in its uppermost position when the parts come to rest. I

From the foregoing description it will be noted that the fluid which serves to shiftthe main valve 45 back and forth is supplied to the. opposite ends of this valve from the low pressure chamber 65 and as a result the main valve will always be operated by liquid acting upon the same with a predetermined pressure depending upon the adjustment of the relief valve 77. This is important because the pressure in the/high pressure chamber 58 may vary considerably due to the resistance offered by the tool being,

forced against its work and also to the pressure at which the fluid is supplied to the main valve by the pump 39, but the variations of the liquid within the high pressure chamber will not affect the pressure of the liquid which shifts the main valve, and as a result the main valve will shift to reverse the downward stroke at the same pointin its downward movement irrespective of variations in the pressure of the liquid in the valve chamber 58, or of the resistance with which the tool meets in its cutting operation.

As stated the auxiliary valve 46 is shifted back and forth by the reverse lever 47 best shown in Figs. 1 and 5, and the arrangement is such that this lever may be placed under the control of the reciprocating head 13 to be shifted back and. forth thereby to operate the auxiliary valve, while at the same time this lever is at all times under the immediate control of the operative to be shifted at will to arrest the downward movement of the head 13 and to bring the head at rest atend of this plunger being pointed somewhat to enter either of the adjacent notches 90 formed in a block 91 secured to the frame or column 11. The arrangement is such that a small projection 92 between the two notches 90 prevents the lever from coming to rest in an intermediate position, and holds the lever yieldingly in one predetermined position or the other.

It is desirable that the lever 47 whi h is pivotally mounted upon the frame 11 by the pin 47 be shifted from one position to the other by the movement of the head 13 towards or from the work, and tothis end, ad-

justable stops are carried 'by the slidingv head 13 to operate the lever. These stops in the present instance comprise adjustable nuts 93 and 94 (see Fig. 3) mounted upon a threaded bolt 95 carried by a U-shaped bracket 96 secured to the sliding head 13. Each adjustable nut 93 and 94 may be locked in its adjusted position by a lock nut 97.

It is desirable to provide the reversing lever 47 with means for placing the same under the control of the adjustable stops 93 and 94, and for releasing it from the 001113101 of these stops at the will of the operative; and to this end, a finger 98 is pivotally secured to the lever 47 and positioned to pro- I then the other.

ject into the path of movement of said stops. The finger 98 has a head 99 rotatably secured to the lever by a pin 100, and the head has a shallow notch 101 and a deep. notch 102. When it is desired that the lever 47 be shifted by the traveling stops, the finger 98 is locked in the position shown'in Fig. 5 by a sliding bolt 103 that enters the deep notch 102. As long as the finger 98 is locked in this position it will be engaged by the stops 93 and 94 and the lever 47 will be shifted to shift the auxiliary valve, which in turn operates the main valve to effect movement of the piston 19 in first one direction and When it is desired to stop the reciprocating movement of the sliding head 13, the bolt 103 is retracted-bythe operative, in a manner to be described, whereupon as the stop 94 moves upwardly it will strike the finger 98, but instead of rocking the lever 47 it will rotate the finger upwardly out of the path of the stop, and the finger will be frictionally held in this new position by engagement of the bolt 103 with the shallow notch 101. The finger 98 will remain in the inactive position until the lever 47 is rocked by the operative, to effect a downward movement of the sliding head 13, whereupon the lower faceof the stop 94 will strike a surface 104 of the head 99, which surface was moved into the path of the stop by the upwardly rocking movement of the finger 98, as will be apparent from Fig. 5. Engagement of the stop 94 with the surface 104 rocks the finger 98 downwardly into position to bring the deep notch 102 into position to be engaged by the bolt 1.03. As the downward movement of the head 13 continues after the lower stop has engaged the surface 104, the upper stop 93 will strike the finger 98 which is now locked in its active position and the lever 47 will be shifted to e'fiect an upward movement of the tool. .Whereupon, the tool will be reciprocated up and down through a distance defined by the adjustment of the stops 93 and 94, until the bolt 103 is again retracted. The bolt 103 is projected by a spring 105 positioned between a pin 106 and an end of the bolt,and the spring and bolt are preferably mounted in a slot formed longitudinally in the lever 47.

The mechanism just described effects automatic reciprocation of the head 13 and the length of the stroke either toward or from the work may be controlled by adjusting the stops 93 and 94, but it is desirable to provide means under the control of the operative to stop the reciprocating movement'of the head, and to bring the head to rest in its uppermost position, and means to this end will now be described;

In the present instance the reverse lever 47 is shifted by a treadle 107, although other means adapted to be controlled by the operative might be provided. The treadle 107' is pivoted at 108 to-swing in a vertical plane and has a part 109 to be engaged by the foot of the operative. The lever is urged upwardly by a spring: 110, and its upward movement may be limited by an adjustable bolt 111. Connected to the treadle 107 is an upwardly extending bar 112 the upper portion of which has a notch 113 adapted to receive the block 114 secured vto the rear end of the lever 47 (see Fig. 5). The bar 112 is urged towards the block 114 by a spring 115 within the head 116 secured to the frame 11, and as the treadle is depressed the notch 113 of the bar is moved away from the block 114 by a fixed pin 117 that engages an inclined surface 118 of the bar 112. The arrangement is such that as long as the treadle 107 is in its uppermost position, the bar 112 will remain'in the position shown in Fig. 1 in which the cutaway portion 119 of the bar permits the notch 113 to engage the rear end of the lever 47 and holds the lever in the upper position as.

shown in Fig. 1. This is the position of the lever that effects movement of the piston 19 to the upper end of its stroke.

As stated, the sliding bolt 103 that locks the finger 98 in its operative position may be retracted by the operative. This is ac complished in the present case by lateral movement of the bar 112. When the operative removes his foot from thetreadle thebar 112 moves upwardly and is'moved towards the block 114 by the pressure of the spring 115, and this movement serves to retract the bolt 103 to release the finger 98. The bar 112 carries a block 120 positioned to abut the rear end of the sliding pin 121 to move this pin frontwardly. A rocking lever 122 is pivotally mounted at 123 upon the reverse lever 47, and one ehd of the lever 122 lies adjacent the forward end of the pin 121, while the opposite end of this lever enters a notch in the sliding bolt 103; the arrangement being such that when the block 120 strikes against the sliding pin 121 it rocks the lever 122 to retract the sliding bolt 103.

From the mechanism just described it will be seen, that the lever 47 normally re- "mains in the upper position shown in 1, with the piston at the upper end of its stroke, and with the bolt 103 retracted, so that the finger 98 may be rotated to its active position. As the treadle 107 is depressed it pulls the bar 112 downwardly and this bar, due to the engagement of the notch 113 with the reverse lever, moves the lever to the lower position. Further downward movement of the treadle causes the bar 112 to be moved rearwardly by the cam 118 out of engagement with the lever. To avoid any possibility of the notch 113 failing to engage the block 114 to shift the lever when the foot treadle 107 moves upwardly, the bar 112 may be provided with a finger 124 that engages the under face of the lever 47 and insures that the lever be rocked upwardly. I

As stated, the reverse lever 47 serves to operate the auxiliary valve 46, and in the embodiment of the invention shown a lever 125 is provided to impart the rocking movement of the reverse lever 47 to the valve 46. The lever 125 may be pivotally mounted upon a bolt 126 supported by the frame 11, and the upper end of this lever is forked, as best shown in Fig. 6, to straddle the outwardly extending end of the valve 46, and is notched to receive a pin 127 extending transversely through the outwardly extending portion of the valve 46. The lower end of the lever 125 is rounded as at. 128 (see Fig. 5) and this rounded end extends into an inclined slot 129 formed within a bracket 130 secured to and extending upwardly from the reverse lever 47. The arrangement is such that when the lever 47 is rocked from one position to the other it shifts the lever 125 to move the auxiliary valve 46 from the position shown in Fig. 6 to the position shown in Fig. 7

From the foregoing description it will be understood that the main valve 45 is shifted by the pressure of the liquid within the low pressure chamber 65. It is possible that under some conditions the downward movement of the piston 19 may be arrested by the tool 14 before the end of the downward stroke is reached and this might prevent liquid from entering the low pressure chamber, with the result that sufficient pressure would not be established in this chamber to shift the main valve 45. Should this condition occur the present invention contemplates positive means for moving the main valve to a predetermined position and to this end a second lever 131 may be mounted adjacent the lever 125, and upon the supporting pin 126, and the lower'end of the lever 131 is provided with an inclined face 132 positioned to be engaged by the upper end of the ha? 112 when this bar is moved to its uppermost position by the upward movement of the foot treadl-e 107. Engagement of the upper end of the bar 112 with the inclined face 132 of this lever rocks the same to the position shown in Fig. 2 and as soon as the foot treadle is depressed to move the bar 112 downwardly the lever 131 will be rocked in the opposite direction by the compressed spring 133. Movement of the lever 131 to the position shown in Fig. 2, and in dotted lines in Fig. 6 serves to pull the main valve to the right viewing Fig. 6, and this is the position which admits liquid to the under side of the piston 19 to hold the latter in its uppermost position. The rocking movement of the lever 131 is conveniently imparted to the main valve 45 by a bolt 134 that extends into the chamber 54 through a stulfing-box 135, and a head 136 upon the inner end of this bolt extends freely into a bore 137 formed Within the main valve and which bore is closed by a nut 138. The arrangement is such that as long as the bolt 134 remains in the position shown in full lines in Fig. 6 the main valve 45 will move back and forth without being affected by the pin 134 but as soon as the lever 131 is shifted to the position shown in dotted lines in Fig. 6 the bolt 134 will be pulled outwardly due to the engagement of the upper end of the lever 131 with a head 139 upon the outer end of this bolt, and this will cause the head 136 upon the inner end of the bolt to engage the nut 138 and positively pull the main valve 45 to the position shown in Fig. 6. It will therefore be seen that the construction just described insures that the main valve will be shifted to a position to move the head 13 to its uppermost position as soon as the treadle 107 is released to move to its uppermost position.

It is often desirable to provide means for relieving the tool being operated from excess pressure which might break or damage the same, and this may be readily accomplished in the present case by providing the pump 39 with a relief valve 140 which may be adjusted to determine the pressure at which liquid will be forced to the hydraulic operating means. As a result the feeding pressure upon the tool 14 will not exceed the predetermined pressure at which the liquid is delivered to the hydraulic operating means and in this manner the maximum pressure to which the operating tool 14 will be subjected may be accurately controlled. It may happen that a small amount of air will find its way into the upper part of the piston chamber 22; to

permit the escape of this air a valve 141 (see Fig. 1) may be provided at the upper end of the cylinder 18 and conduits 142 and 143 (see Figs. 8 and 9) may be provided to form a communication between this valve and the curved conduit 75.

The operation of the mechanism for reciprocating the head 13 is briefly as follows:

The reverse lever 47 is normally held by the bar 112 in the position shown in Fig. 1, and reciprocating movement is imparted to the head 13 upon depressing the foot treadle 107. This rocks the lever 47 downwardly and places the same under the control of the traveling stops 93 and 94 which shift the lever back and forth to reverse the movement of the head 13. This movement of the lever 47 shifts the auxiliary valve 46 to admit liquid to one end or the other of the main valve 45 to thereby shift the main valve to admit liquid under pressure to one end of the cylinder 18 or the other.

As soon as the operative removes his foot from the treadle 107 the lever 47 is automatically rocked upwardly to admit liquid to the under side of the piston 19 so that the head 13 will be carried to its upper most position and will be held in this position by the counterbalancing spring 38 and also by the pressure of the liquid that flows into the cylinder through the port 53. and escapes from this cylinderthrough the passages 86 to the low pressure chamber.

From the foregoing description when read in connection with the'drawings it will be seen that the hydraulic means of-the present invention is Welladapted to operate various different types of tools, and that the present device may be readily adjusted to vary the length of stroke and the point at which the reverse movement will be effected; that the tool operating head will automatically return to its uppermost position when the operative removes his foot from the treadle; that the parts will operate smoothly, and may be operated at any desired speed by varying the speed at which the operating fluid is delivered to the hydraulic cylinder; that the maximum pressure of feed upon the tool may be accurately controlled by controlling the maximum pressure of the operating liquid; and that the present construe-- tion possesses various other advantages.

VVhat is claimed is:

1. In a machine of the class described, a frame, a sliding head supported by the frame, hydraulic means for imparting reciprocatory movement to the head including a cylinder containing a piston operatively con- .nected to the head, a main valve for controlling the pressure of an operating liquid upon the opposite sides of the piston, a low pressure chamber for receiving the exhaust liquid from the cylinder and having a pressure relief valve for maintaining a predetermined pressure in said chamber and means for subjecting the main valve to the pressure of the liquid in the low pressure chamber to shift said valve including an auxiliary valve mechanically shifted to control the action of the liquid upon the main valve.

2. In a machine of the class described, a frame, a sliding 'head supported by the frame, hydraulic means for imparting recip-- rocatory movement to the head including a cylinder containing a piston operatively connected to the head, a valve casing having a high pressure chamber and a low pressure chamber, a main valve for controlling the flow of the operating liquid from the high pressure chamber to the piston cylinder, means for subjecting the opposite ends of the main valve alternately to the pressure of the fluid of the low pressure chamber to shift the main valve and including an auxiliary valve for controlling the liquid that-shifts the main valve.

3. In a machine of the class described, a

supporting frame, a sliding head upon the frame, hydraulic means for imparting reciprocatory movement to the head including a cylinder containing a piston voperatively connected to the head, a main valve for controlling the pressure of an operating liquid upon the piston, a pressure chamber provided with means for maintaining the liquid therein ata constant pressure not affected by'v'ariations in the pressure insaid cylinder, conduits leading from said 'n'essurechamher to the opposite ends of th main valve to subject the main valve. to the action of the pressure in said chamber, and an auxiliary valve for controlling said conduits to thereby control the shifting of the main valve by the pressure of the fluid upon its opposite ends.

4, In a machine of theclass described, a

supporting frame, a sliding head upon, the fran1e,hydraulic means for imparting reciprocatory movement tothe head including a actuating the auxiliary valve to shift the main valve.

5. In a machine of the class described, a supporting frame a sliding head upon the frame, hydraulic means for imparting reciprocatory movement to the head including a cylinder containing a piston operatively connected to the head, a main valve for controlling the pressure upon the piston, a low pressure chamber into which the exhaust fluid from the cylinder is discharged and provided with a relief valve for maintaining a predetermined pressure in said chamber means for subjecting the main valve to the action of the fluid in the low'pressure chamber to shift the main valve and including an auxiliary valve for controlling the'aetion of the fluid on the main valve, and a port leading from the cylinder to the low pressure chamber and controlled by the movement of the piston to supply fluid to the low pres-.

sure chamber while the piston is arrested at one end of its stroke.

6. In a machine of the class described, a supporting frame, a sliding head upon the frame, hydraulic means for imparting reciprocatory movement to the head including a vertically disposed cylinder containing a piston, a piston shaft secured to the piston 6 from said cylinder and having a relief valve for maintaining a predetermined pressure therein, means for subjecting the main valve to the action of the fluid in the loW pressure chamber to actuate it and including an auxil- 10 iary valve for controlling the action of the fluid on the main valve, and a port formed in the piston shaft for the passage of fluid from the cylinder to the low pressure chamber and opened by the movement of the piston to the upper end of its stroke to supply a continuous flow of fluid to the lOW pressure chamber as long as the cylinder is arrested at the upper end of its stroke.

7. In a machine of the class described, a

supporting frame, a sliding head upon the frame, hydraulic means for imparting re ciprocatory movement to the head including a cylinder containing a piston connected to said head, ports for delivering the fluid to the opposite ends of said cylinder, a main valve for controlling the ports, fluid actuated means for shifting the main valve including a low pressure chamber into which the cylinder exhausts and an auxiliary valve for controlling the pressure of the fluid in the low pressure chamber upon the main valve, and a passage constructed to be opened by the movement of the piston to one end of its stroke to permit fluid to flow continuously into the cylinder through one port and out of the cylinder through said passage into the the low pressure chamber to supply said chamber With fluid under pressure as long as the cylinder isarrested at one end of its stroke.

8. In a machine of the class described, a supporting frame, a sliding head upon the 'frame, hydraulic means for imparting reciprocatory movement to the head including a cylinder containing a piston connected to said head, ports for delivering the fluid to the opposite ends of said cylinder, a main valve for controlling the ports, a low pressure chamber into which the cylinder exhausts, a relief valve for maintaining a predetermined pressure in the low pressure chamber, conduits leading from the loW pressure chamber to actuate the main valve by subjecting it to the pressure of the low pressure chamber, an auxiliary valve for controlling the actuating pressure upon the main valve, a port leading from the cyl'in der to the low pressure chamber and adapted .to be opened by the movement of the piston to one end of its stroke whereby one face of the piston is subjected to the constant pressure of the low pressure chamber to hold the piston at the end of its stroke.

9. In a machine of the class described, a supporting frame, a sliding head upon the frame, hydraulic means for reciprocating the head including a cylinder containing a piston, means for delivering a continuous stream of liquid to the cylinder under pressure, a main valve for controlling the flow of liquid to the opposite ends of the cylinder, a low'pressure chamber provided with a relief valve for maintaining a constant valve to the pressure of the low pressure chamber to actuate it including an auxiliary valve operable to control the actuating pressure upon the main valve.

10. In a machine of the class described, a supporting frame, a sliding head upon the frame, hydraulic means for reciprocating the head including a cylinder containing a piston operatively secured to the head, a main valve for controlling the How of fluid to the opposite ends ofthe cylinder, fluid pressure means for shifting the valve to its different positions including an auxiliary valve, treadle controlled means for shifting the auxiliary valve, and additional means controlled by said treadle and operable to mechanically engage the main valve and move it to a predetermined position.

11. In a machine of the class described, a supporting frame, a sliding head upon the frame, hydraulic means for reciprocating the head including a cylinder containing a piston operatively secured to the head, a main valve for controlling the fluid pressure upon the opposite faces of the piston, fluid pressure means including'a second valve for shifting the main valve, a reverse lever for shifting the second valve to its different positions, means carried by said head to shift the reverse lever, treadle controlled means movable to one position to start the reciprocation of said head and toplace the reverse lever under the control of the head and movable to a second position to relieve the reverse lever from the action of said head, and means operable independently of said fluid pressure and upon movement of the treadle to shift the main valve to a predetermined position.

12. In' a machine of the class described, a supporting frame, a sliding head upon the frame, hydraulic means for reciprocating the head including a cylinder containing a piston operatively secured to the head, a main valve for controlling the fluid pressure upon the opposite faces of the piston, fluid pressure means including a second Valve for shifting the main valve, treadle controlled means for starting and stopping the reciprocatory 'ond valve so that it will hold the main valve in one of its positions, and mechanical means operable by the treadle to move the main valve independent of the fluid pressure to a predetermined position as the piston comes to rest. v

13. In a machine of the class described, a supporting frame, a sliding head upon the frame, hydraulic means for reciprocating the head including a valve, a reverse lever operable when moved to one position to effect through the hydraulic means movement of the head toward the work and when moved to a second position to effect through. the hydraulic means movement of the head from the work, stops mounted to travel with the head and adapted to shift the lever from one position to the other, treadle controlled means for releasing the lever from the control of said stops by effecting movethe frame, hydraulic means for reciprocating the head including a cylinder containing a piston operatively secured to the head,

a main valve for controlling the flow of fluid to the opposite ends of the cylinder,

fluid actuated means for shifting the main valve including an-auxiliary valve for controlling the fluid that actuates the main valve, means actuated by the reciprocating head to shift the auxiliary valve, treadle controlled means for imparting initial and final movement to the auxiliary valve and for placing the latter under the control of the reciprocating head and for releasing it from the control of said head, and additional means operable by said treadle to engage the main valve and move it to a predetermined position as the head comes to rest.

15. In a.v machine a frame, a sliding head supported by the frame, hydraulic means for imparting reciprocatory movement to the head including a cylinder containing a piston operatively connected to the cad, a valve for controlling the operating pressure upon said piston, a reverse lever for operating said of the class described,

valve and adapted fie be shifted by the travel of said head to limit the back and forth movement of the head, a projection upon the reverse lever which is normally locked in position to shift thelever, treadle control means operable independently of the travel of said head to simultaneously move the reverse lever to a predetermined position and release said projection so that 1t will permit the head to move to the limit of its stroke, and additional means operated by said treadle to move said valve to a predetermined position.

16. In a machine of the class described, a frame, a sliding head supported thereby, hydraulic means for imparting reciprocatory movement to the head including a cylinder having a piston connected to the head, a high pressure chamber having a main valve for controlling the flow of fluid means for controlling the pressure in the low pressure chamber, and an auxiliary valve for controlling the action of the low pressure fluid upon the main valve.

I 17. In a machine of the class described, a supporting frame, a sliding head supported by the frame and having a bracket provided with spaced laterally extending portions to receive the piston shaft, fluid actuated means for imparting reciprocatory movement to the head including a cylinder having a iston'therein, a piston shaft secured to t e piston and extending between said spaced, laterally extending portions, a connection between the piston shaft and sliding head and constructed to permit a slight lateral play between them, comprisinga spool bored to receive said shaft and ri idly secured thereto and having its bo y portion disposed between said spaced portion, and, heads at the opposite ends of the spool which abut against said portions and permit lateral movement of the spool between said portions.

In testimony whereof, I have signed "my name to this, specification.

ALPHONZO WHITE. 

